Railway traffic controlling apparatus



a ITR 212112 ZENTEPRH gamma 3* 3--'-- June 23, 1942. I M ALLEN ET A 7 2,287,078

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Oct. 4, 1940 ITRE 1302M ZLTER I JZDPR IIDPR A]? 213T EPR RHR THEIR ATTbRNEY Patented June 23, 1942 RAILWAY TRAFFIC CONTROLLING APPARATUS Earl M. Allen, Swissdale, and Henry S. Young;

Wilkinsburg, Pa...

assignors to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application October 4, 1940, Serial No. 359,700

16 Claims.

Our invention relates to railway traffic controlling apparatus, and it has particular reference to the organization of such apparatus into novel and improved railway trafiic controlling systems for controlling the operation of either or both railway signals. and track switches.

Interlocking systems heretofore proposed for controlling either or both railway signals and track switches ordinarily incorporate approach locking means rendered efiective upon the approach of a train to prevent alteration of the route established for such train. Such systems incorporate means for efiecting a normal or track circuit release of such approach looking when the train accepts the established route, and also incorporate means for efiecting a time release of such looking after enforcing a predetermined time delay. Where .call-on signals are incorporated into such interlocking systerns, it has been customary to maintain such approach locking efiective when a call-on signal is displayed by utilizing a stick relay controlled by the call-on signal lever or button and retained energized over a stick circuit controlled by the control relay of the call-on signal. Such systems rely upon the integrity of the stick circuit of the call-on control relay, since ordinarily no means is provided for checking the holding circuit of the call-on control relay and if such circuit should fail,.the stick relay might release to permit an improper release of the approach locking when the callon signal is being displayed. 7

In view of the foregoing and other important considerations, it is an object of our present invention to provide a railway traffic controlling system of the above described class incorporating novel and improved means for positively maintaining the approach locking when a callon signal is being displayed.

Another object of our invention is to provide a remote control or interlocking system of the class described above and incorporating novel and improved means including a polarized relay for maintaining the approach locking when a call-on signal is being displayed. A further object of our invention is to incorporate into a system of the class described, novel and improved means controlled by such polarized relay for preventing a time delay in the release of the approach locking when a slow speed route is established but the slow speed or call-on signal does not clear.

An additional object of our invention is to incorporate such polarized relay in a system of the class described, in such a manner as to obtain progressive signaling whereby after a call-on signal has been cleared, a high speed signal may be cleared automatically instead of the call-on signal in the event that traific conditions alter to permit such high speed signal.

Another object is to provide such progressive signaling in a railway traific controlling system in such manner that after a train accepts a high speed signal which has been substituted'for a call-on signal, the call-on signal will not reappear automatically but will be displayed only if the operator takes the steps necessary to clear such call-on signal. 7

An additional object is to provide a railway traffic controlling system wherein there is introduced into the control of high speed and slow speed signals a polarized relay arranged to check the route which each signal governs.

A'further object is to provide an improved railway traffic controlling system wherein there is incorporated into the control of a high'speed' signal a polarized relay controlled by traific conditions in the section associated with such signal, whereby track circuit control or slotting of such signal is attained.

Another object of our invention is to provide an improved railway trafiic controlling system having novel and improved means for providing long and short time releases with checking contacts to check the return of the time element device to normal after the employment of either the long or short time release.

-A further object of our invention is to provide a system of the class described wherein novel and improved means is provided to prevent a track circuit release of the approach locking when a slow speed signal is employed as a callon signal, but which permits such track circuit release of the approach locking when the slow speed signal is employed for a diverging route. I

Another object of our invention is to provide a system of the class described wherein novel and improved means is provided to enable the approach locking relay to pick up without a time delay in the event that the operator fails to restore the signal lever to its normal position when a train accepts a signal.

The above-mentioned and other important objects and characteristic features of our invention which will appear as the description proceeds, are attained by incorporating a polarized relay into a railway trafiic controlling system of the class described. The polarized relay is controlled by switch repeater relays, track circuits, signal control lever contacts and by the call-on lever or push button in such manner as to be energized in a normal direction only when traffic and track conditions are favorable for a high speed signal to be cleared, and to be energized in its reverse position whenever a signal is cleared under conditions unfavorable for a high speed signal.

Other important features of the use of the polarized relay reside in the specific arrangement and organization of the circuits controlled by such relay. We shall describe a preferred form of apparatus embodying our invention, and shall then point out the novel features of our invention in claims.

The accompanying drawing is a diagrammatic view illustrating a preferred form of apparatus embodying our invention.

Referring to the drawing, the diagram at the top represents a stretch of railway track comprising a track section IT intermediate an approach section AZT and another section OZT. Each section is provided with the usual closed circuit track circuit including a normally energized track relay as indicated diagrammatically in the drawing, these relays being designated by the reference characters ITR, A2TR and OZTR, respectively. Section IT also includes a track switch I connecting a passing or siding track 4 to section IT, and another switch 3 which connects a diverging track 5 to section IT.

Switch I is actuated by a power operated switch mechanism ISM controlled in the usual manner, not shown, and is provided with a polarized switch repeater relay IWPR' controlled over, pole changing contacts I and 8 associated with mechanism ISM, to a normal position in which the relay is shown, when switch I is normal and to a reverse position when the switch is reversed. Similarly, switch 3 is operated by a power actuated switch mechanism 3SM alsocontrolled in the usual manner, not shown, and has associated therewith a polarized switch repeater relay 3WPR controlled to normal and reverse positions in accordance with the normal and reverse positions of the switch as indicated by movable pole changing contacts I and 8 associated with mechanism 3SM. In order to simplify the drawing, we have omitted showing the circuit which control the operation of witch mechanisms ISM and 3SM, but it is to be understood that such circuits in accordance with the usual practice are controlled by an approach locking relay 2RASR, hereinafter referred to in detail, in such manner that operation of the switches may be effected when and only when relay ZRASR is picked up.-

The movement of traffic on the main track into section IT in the normal direction from left to right as viewed in the drawing is governed by a signal 2R comprising a high speed signal unit ZRA which normally indicates stop but which may be cleared to indicate proceed when sections IT and OZT are unoccupied and switches I and 3 are normal; and an auxiliary slow speed or call-on signal unit 2R0 which may be cleared to permit a train operating in the normal direction of traffic on the main track to enter section IT when switch 3 is reversed and/or section IT or OZT is occupied by a preceding train. The movement of trafiic from track 4 into section IT is controlled by a signal 2RD which may be cleared when switch I is reversed. The movement of traffic on the main track into section IT against the normal direction of traflic is controlled by a slow speed signal ZLA, which may be cleared if switch 3 is normal; and the movement of traffic from track 5 into section IT is governed by a signal 2LB which may be cleared when switch 3 is reversed.

The above-mentioned signals may be of any desired type, but as illustrated in the drawing are Searchlight signals which may, for example, be of the type disclosed and covered in Letters Patent of the United States, No. 1,864,224, granted to Wesley B. Wells on June 21, 1932, for Light signals. Signal unit 2RA, for example, comprises an armature I5 mounted to rotate between an intermediate position to which it is biased, and at least one extreme position, Armature I5 is controlled by an armature winding I6, and is arranged in such manner that when the winding is energized, the armature will rotate clockwise to its right-hand extreme position. Attached to armature I5 to rotate therewith are at least two colored roundels G and R, which are arranged to be disposed in the path of a beam of light projected from an associated lamp I'I according as the armature I5 occupies its right-hand extreme position or its intermediate position. For convenience in illustration, lamp IT in the drawing is shown disposed above the associated roundels, but it will readily be understood that in actual practice lamp I! will be located directly back of the associated roundels, and will have associated therewith a suitable optical system, not shown, for projecting a beam of light from the lamp.

Signal ZRA indicates stop or proceed according as roundel R or roundel G is in front of its associated lamp I'I when this lamp is lighted. Operatively connected with armature I5 is a circuit controller comprising two movable contact fingers I8 and I9. The movable contact finger I8 cooperates with a fixed contact I8b to close a contact I8-I8b when armature I5 occupies its intermediate position, but which contact is opened when armature I5 occupies its right-hand position; while movable contact member I9 cooperates with a fixed contact I91) to close a contact I9--I9b in both the intermediate and the right-hand positions of armature I5. Other movable contact members 20 and 2| are controlled by armature I5 to close contacts 26-261) and ZI-ZIb in the intermediate position of armature I5, contact 2020b being opened when armature I5 is in its righthand position.

The signal lamps I1 may be either normally dark as shown and approach lighted; or if desired such lamps may be normally illuminated. We have not shown in the drawing the circuits 'over which lamps I! of the several signals are approach energized, but it is to be understood that such lamps are energized by circuits controlled in the usual manner whereby there is attained approach lighting of the signals.

Control of the signals is established through the medium of a manually operable control lever .V, which may, for example, be a signal control lever of an interlocking machine located at a point remote from the signals. Lever V normally occupies a normal position N, and is movable to one extreme position R to condition the control apparatus, hereinafter described in detail, to es-- tablish control over signal 2R or 2RD; and to another extreme position L wherein the control apparatus is conditioned to control signal 2LA or ZLB. Lever V is provided with a plurality of circuit controlling contacts, each selectively closed in accordance with the position of the lever. Each contact of lever V bears one or more reference characters N, R or L, to indicate the different positions of the lever in which such contact is closed. For example, contact 4'! of lever V bears the reference character NL to indicate that this contact is closed when the lever is in or intermediate its normal N and left L positions; while contact 49 of the lever bears the reference character NR to indicate that such latter contact is closed whenever the lever is in or intermediate its normal N and right R positions. In order to simplify the drawing, certain of the lever contacts are shown located remote from the lever, but in each case such contacts have been identified by th reference character of the lever operating such contacts; by an identifying reference character referring to the particular contact in question; and by the reference character N, R or L designating the positions of the lever in which such contacts are closed.

Associated with signals 2R and 2RD there is a polarized control relay ZRHR of the type which retains its polar armature in its last operated position. Relay ZRHR is energized in its normal direction when and only when conditions are safe for signal ZRA to display its proceed indication. Such conditions exist if switches and 3 are normal and sections IT and OZT are unoccupied, as will be made clear presently. With switch 3 reversed; or with switch 3 normal and switch I reversed; or with both switches normal, section IT and/or O2T occupied, lever V in its right position R, and a manually operable push button COPB actuated, relay ZRHR is energized in its reverse direction in a manner to be explained as the description proceeds.

Also associated with signals 2R and 2RD is an approach locking relay ZRASR, and associated with this relay are a time element relay ZRTER, a repeater relay 2RNTEPR, and a slow releasing stick relay ZR'I'ESR. Relay ZRASR is normally energized when signal units ZRA, 2RC and 2RD are at stop, lever V is normal, and section AZT is unoccupied. Alternate paths controlled by relays ZRHR, I'IR and 2RTESR are provided in the circuit of relay ZRASR, and these alternate paths will be pointed out in detail when the circuit of relay ZRASR is traced hereinafter.

The time element relay ZRTER may be of any suitable type such as, for example, the thermal relay illustrated and described in Letters Patent of the United States, No. 2,114,895, granted on April 19, 1938, to Harry E. Ashworth for Thermal relay. Relay ZRTER is provided with a thermal element 24 effective to close a time contact 25 at the end of a predetermined interval of time after energization of the relay, and with a checking contact 26 which opens shortly after the energization of the relay and closes only when time contact 25 assumes its normal position. Relay 2RTER is normally deenergized so that checking contact 25 is closed to complet for relay ZRNTEPR an obvious energizing circuit, which circuit becomes opened to release relay ZRNTEPR upon energization of relay ZRI'ER over a circuit controlled by back contact 45 of relay ZRASR and signal units 2RA, 2RC and 2RD at stop. After time contact 25 of relay ZRTER closes, relay ZRTESR becomes picked up over a circuit which includes time contact 25 of relay 2RTER; and relay 2RTESR also is provided with a stick circuit path including its own front contact 80 which shunts time contact 25 of relay ZRTER.

Signals ZLA and ZLD also are provided with an approach locking relay ZLASR and a time element relay 2LTER, which relays correspond in functions to relays ZRASR and 2RTER, but the circuits for relays ZLASR and 2LTER have been omitted in order to simplify the drawing.

In order further to simplify the drawing, we have represented relay contacts at times disposed remote from the relays which cause them to operate, but in each case such contacts bear the reference characters identifying not only the respective relay operating such contacts but also a number individual to each of such contacts. For example, the reference character ITR has been placed immediately above front contact 28 to indicate that this contact is operated by re- The apparatus is in its normal condition, as

represented in the drawing, when sections A2T, IT and O2I are unoccupied and switches l and 3 are locked in their respective normal positions. In this normal condition of the apparatus, all signals are conditioned to display their stop indications; lever V is in its normal position N; and relay ZRHR is energized in its normal direction over a circuit extending from one terminal B of a suitable source of current, such as a split battery 46 having a mid terminal C and two opposite terminals A and B, through front contact 28 of relay ITR, front contact 29 of relay O2TR, normal polar contact 30-3! and front contact 32 of relay IWPR, normal polar contact 33-34 and front contact 35 of relay 3WPR and the winding of relay 2RI-IR to a common terminal C of the course of current. Approach locking relay ZRASR also is energized over its normal circuit which may be traced from "terminal B through contacts !8-!8b and [Sb-l 9 of signal units 2RD, 2R0 and ZRA, respectively, contact .31 of lever V, front contact 38 and normal polar contact 3940 of relay IWPR, front contact 4! of relay AZTR, front contact 42 of relay ZRNTEPR, normal polar contact 4344 of relay ZRHR, and the winding of relay 2RASR to terminal C. With relay 2RASR energized, its front contact 45 is closed to complete an obvious stick circuit path around the contacts of relays IWPR, AZTR, 2RNTEPR and ZRI-IR interposed in its just traced normal circuit. Also, relays ZRTER and ZRTESR are released, but relay ZRNTEPR is energized over the circuit including normally closed checking contact 25 of relay ZRTER.

To clear signal unit ERA of signal 2R for a train operating over the main track in the normal direction of traffic, the operator moves lever V to its right position R, thereby opening at contact 3! of lever V the previously traced normal energizing circuit of relay ZRASR, which relay thereupon releases, and closing at contact 53 of lever V a proceed circuit for unit ZRA of signal 2B, which circuit may be traced from terminal B through front contact 48 of approach locking relay ZLIASR provided for signals 2L, contact 49 of lever V, front contact 53 of relay fill PR, front contact 5! of relay IWPR, back contact of relay ZRTESR, lever contact 53, back contact 54 of relay ZRASR, normal polar contact 5556 and front contact 5! of relay ERHR, and winding !5 of signal unit ZRA to terminal C. Signal unit ZRA is now conditioned to display its proceed indication, and if lamp I! of unit ZRA of signal 2R becomes approach energized due to the approach of a train, signal unit ZRA will display its proceed indication.

It is to be noted that the route established for the train, and traflic conditions in advance of such route, are evidenced by polarized relay SRHR, which must be energized in its normal direction in order that high speed signal unit ZRA might be cleared. Inasmuch as contacts of the switch repeater relays IWPR and 3WPR are introduced into the circuits of relay ZRI-IR as well as into the signal control circuit, it is evident that improper routing such as might be caused by crosses, grounds, etc., are protected against in much the same manner as that heretofore obtained in a two-wire, double break system wherein wires of the signal control circuit extending to both terminals of the operating source of current are carried through contacts of the control apparatus.

When the approaching train occupies section AET, relay AZTR releases to open front contact ii in the normal circuit of relay ZRASR, and when the train occupies section IT, relay ITR releases to open front contact 28 and thereby open the normal energizing circuit of relay The releasing of relay 2RHR of course causes its front contact 51 to open and thus open the previously traced proceed circuit of signal unit ZRA, whereupon that signal unit automatically goes to stop, and back contact 60 of relay 2r HR closes to complete around lever contact 3'! in the normal circuit of relay ZRASR. an alternate path. Back contact (if of relay 'ITR is now closed and completes around front contact 38 and normal polar contact 3940 of relay iW'PR and front contact 4| of relay AZTR, which la ter contact is open with the train in approach section AZT, an alternate path in the circuit of relay SRASR, and it follows that when the train occupies section IT and signal unit ZRA automatically goes to stop, relay ZRASR is caused to pick up regardless of whether lever V is restored to its normal position or not, over a circuit extending from terminal B through contacts 58-58?) and i9b--l9 of signal units ERA,

and 2&1), respectively, back contact GB of relay l-ERHR, back contact 6| of relay ITR, front contact &2 of relay 2RNTELPR, normal polar conof relay ZRHR, and the winding of r ZRASR to terminal C. It is, of course, obv1.- s that if the operator properly restores the lever to its normal position after the train enters section lT, lever contact 31 is closedin multiple with back contact 63 of relay ZRHR in the just traced circuit of relay ZRASR. It follows that track circuit release of the approach looking is effected when a train accepts the proceed indication of signal unit ZRA.

In the event that switch 3 is reversed, operaticn of lever V to its R position will clear slow speed signal unit ZRC of signal 23 or signal unit 3RD according as switch I is in its normal or reverse position respectively. That is to say, with switch 3 reversed to cause relay 3WPR to operate to its reverse position, the previously traced normal circuit of relay ZRHR is opened at normal polar contact 3334 of relay SWPR and an obvious reverse energizing circuit is completed for relay ZRHR extending from terminal A of the source of current through reverse polar contact 6234 and front contact 35 of relay SWPR and the winding of relay ZRHR to terminal C. With relay ZRHR energized in its reverse direction, the opening of lever contact 3'! when the lever is operated to its R- position and the consequent release of relay 21RASR to close its back contact 54, completes a circuit for si unitZRC or 2RD, which circuit corresponds to the circuit previously traced for signal 2RA up to polar contact member 55 of relay 2RHR, and then extends from that member through reverse polar contact 55-63 of relay 2RHR, front contact E4 of relay ZRNTEPR, then either through reverse polar contact 55-61 of relay IWPR closed if switch I is reversed, and winding IE or signal unit 2RD to terminal C to clear signal unit 2RD, or through normal .polar contact 65 66 of relay IWPR closed if switch I is normal, contacts 2I-2lb and 2025b of signal unit ZRA closed when that unit is at stop, and winding l5 or" signal unit ZRC to terminal C to clear the latter signal unit. As the train passes cleared signal unit 2R0 or 2RD, as the case may be, the signal unit remains in its clear position but may be restored to stop by the operator restoring lever V to its normal position N. When this is done, contact 53 of lever V opens to cause the circuit of signal unit ZRC or 2RD, as the case may be, to become opened, and such unit accordingly assur'nes its stop position wherein there is completed for relay ZRASR a circuit extending from terminal B through contacts I8'l8b and iii-- 1% of signal units 2RD, 2RC and 2RA, respectively, lever contact 31, back contact Bl of relay ETR, front contact 14 and reverse polar contact 173-44 of relay ZRHR and the winding of relay iRASR to terminal C, and relay 2RASR accordingly picks up to complete its stick circuit at :[ront contact 45, thereby releasing the approach locking of the apparatus.

In the event that a train occupies section IT 1 and/or O2'I to put unit 2RA to stop, and it is desired under such conditions to signal a following train to enter section IT, the operator moves lever V to its R position, and then actuates the manually operable push button COPB. This causes relay ZRHR to be energized in its reverse direction over a circu'itextending from terminal A through contact 10 of lever V, contact ll of push button COPB, back contact 29 of relay OZTR or back contact 28 of relay ITR and front contactEQ of relay OZTR, normal polar contact 3il-3l and front contact 32 of relay IWPR, normal polar contact 3334 and front contact 35 of relay 3WPR, and the winding of relay ZRHR to terminal C, and relay ZRHR is caused to operate its polar contact members to their reverse positions. Push button COPB may now be released, and slow speed or call-on signal unit 2R0 clears over its previously traced circuit, due to the fact that with lever V operated to its R position to open contact 31, relay ZRASR was caused to release to open its front contact 45 when relay ZRHR, became energized to open back contact 50 during the interval that push button COPB was actuated. It should be noted that signal unit 2R0 will not clear under the above assumed conditions unless the route is proper, that is, unless switches l and 3 are normal. It should further be noted that although relay 'iRHR becomes released in its reverse position when push button COPB is released, and relay ZRI-IR closes its back contact 69 to shunt around open lever contact 31, relay 2RASR, remains released since normal polar contact 43-44 of relay ZRI-IR is now open and both front contacts 14 and 15 of relays 2RHR and ZRTESR, respectively, through which relay ZRASR might be energized, are open. Furthermore, with relay ZRASR r-etained released to close its back contact 54, a signal unitZRC is caused to display its proceed indication to thereby cause contact I 9-|9b of unit 2R0 to be opened until such time as the following train accepts the signal and the operator restores lever V to its normal position, unless the preceding train vacates sections IT and O2T prior to the following train accepting the slow speed call-on signal indication. In this latter event, relays [TR and OZTR of course pick up to complete the normal energizing circuit of relay ZRHR, which thereupon becomes energized in its normal. direction to complete at normal polar contact 55-55 the previously traced proceed circuit of signal unit 2RA, and to control unit 2R0 to stop. With unit 2RA cleared and relay ZRI-IR. operated to its normal position, it is apparent that when the following train accepts the proceed indication of signal unit 2RA and enters section IT, unit ZRA is controlled to its stop indication, and the slow speed indication of unit 2R0 does not reappear unless the operator again actuates push button COPB.

Our invention also provides means for obtaining a long or a short time release for the approach locking according as the route attempted to be altered is a high speed or a slow speed route. Such time releases of the approach locking are of course utilized to insure that once a route has been established for an approaching train, such route cannot be altered to a lower speed route until after the elapse of a predetermined time interval sufiicient to enable the speed of the train to be reduced from that permitted under the first established route to that permitted under the altered route.' It is thus evident that if the train is approaching a cleared high speed signal at a high rate of speed, such train requires a relatively longer time in which to be brought to a stop or to a slow speed than does the train approaching a cleared slow speed signal at a low speed, hence it is desirable to establish for a train a relatively long or a relatively short time release according as the signal under which the train has been proceeding is a high speed or a slow speed signal.

Assume now that with signal unit ZRA cleared to indicate proceed and with a train in section A2T, the operator wishes to alter the route established for the train. Under such assumed conditions, relay ZRHR is energized in its normal direction, and relay ZRASR is released, as pointed out previously. To alter the established route, the operator moves lever V to its normal position, thereby opening at lever contact 53 the previously traced proceed circuit of signal unit 2RA, which unit accordingly goes to stop and thus completes for time element relay ZRTER an energizing circuit which extends from terminal B through contacts l8l8b and l 9I9b of signal units 2RD, 2R0 and 2RA, respectively, lever contact 31, back contact 45 of relay 2RASR, back contact 80 of relay ZRTESR, and heating element 24 of relay 2R'I'ER to terminal C. The energization of relay ZRTER causes its checking contact 26 to open and thus deenergize relay ZRNTEPR, so that when time contact 25 of relay ZRTER. closes at the end of the predetermined time interval of relay ZRTER, stick relay ZRTESR. is picked up in multiple with relay ZRTER over a circuit corresponding to the circuit of relay ZRTER. up to the heel of contact 86 of relay ZRTESR, and then passing through time contact 25 of relay 2RTER, back contact 8| of relay ZRNTEPR and the winding of relay 2RTESR to terminal 0. Relay 2RTESR. there upon picks up to open its back contact 80 and thus open the previously traced energizing circuit of relay 2RTER, and to complete a stick circuit over its closed front contact 80. Relay ZRTESR remains energized over its stick circuit until the cooling of heating element 24 of relay ZRTER causes checking contact 26 to close and complete the circuit of relay 2RNTEPR. When this happens, relay 2RN'I'EPR picks up to cause relay ZRASR to pick up over a circuit extending from terminal B through contacts l8l8b and l9l9b of signal units 2RD, ZRC

and 2RA, respectively, contact 31 of lever V, front contact 15 of relay 2RTESR, front contact 74 of relay 2RHR, front contact 42 of relay ZRNTEPR, normal polar contact 43-44 of relay ZRHR and the winding of relay ZRHR to terminal C. When relay ZRASR picks up, its back contact 45 becomes opened to open the stick circuit of relay ZRTESR, which relay thereupon drops at the end of its slow release period, and front contact 45 of relay ZRASR. completes for that relay its stick circuit which holds that relay energized after relay 2RTESR drops and opens its front contact 15 interposed in the last traced pick-up circuit of relay ZRASR.

With approach locking relay ZRASR picked up, the operator may now operate switch I and/ or 3 to the reverse position and thus alter the route which had been established for the train approaching signal unit 2RA. For example, if switch 3 is reversed by the operator, relay 3WPR of course will be operated to its reverse position to energize relay ZRHR to its corresponding reverse position, and the operator may now signal the train to take the diverging track by operating lever V to its right position R, thus causing relay 2RASR to release and close its back contact 54 and thereby in turn clearing signal 2R0 by completing the previously traced circuit of this unit since reverse polar contact 55-53 of relay ZRI-IR is now closed. This circuit over which signal unit 2R0 is cleared checks against improper switch closure in much the same manner as that pointed out hereinbefore that relay ZRHR, checks the circuit of signal unit 2RA. That is to say, if relay ZRHR is operated to its reverse position upon reversal of switch 3, the switch must remain in its full closed reverseposition in order that relay 2RHR may be energized and unit 2R0 may be cleared. In the event that switch 3 creeps open, relay 3WPR releases to open its front contact 50 interposed in the previously traced circuit of unit 2R0 to prevent the clearing of that signal unit when lever V is operated to its right position R, and also to open front contact 35 interposed in the reverse energizing circuit of relay ZRHR. With relay ZRHl-t released to close its back contact 65, the opening of lever contact 31 interposed in the previously traced normal circuit of relay ZRASR does not cause that relay to release and impose the approach locking on the apparatus, hence the operator may restore lever V to its normal position if he sees that signal unit ZRC does not clear, and is enabled toe'stablish another route for the train without requiring the approach locking to be released through the medium of time element relay ZRTER. It follows, therefore, that the use of back contact 60 of relay ZRHR, in the circuit of relay 2RASR. enables an operator at times to change a route quickly in the event that the route that he has attempted to establish cannot properly be obtained.

The short time release is provided by apparatus embodying our invention when the operator Wishes to alter a route established for a train governed by slow speed signal units 2R0 or 2RD. Under such assumed conditions, that is, with a slow speed signal unit cleared, relay ZRHR isin its reverse position and relay ZRASR is released. The operator first puts the slow speed signal unit to stop when he restores lever V to its normal position to open lever contact 53, and after the signal unit assumes its stop position, relay 2RTER is energized over its previously traced energizing circuit in the manner explained heretofore. The energization of relay 2RTER causes relay ZRNTEPR to release upon the opening of checking contact 26, as pointed out hereinbefore, and when time contact 25 of relay ZRTER closes at the end of its predetermined time interval, relay 2RTESR is picked up over its previously traced pick-up circuit. When this happens, front contact I5 of relay 2RTESR completes for relay ZRASR a pick-up circuit which extends from terminal B through contacts |8I8b and Iii-49b of signal units 2RD, 2RC and ZRA, respectively, lever contact 31, front contact I5 of relay 2RTESR, reverse polar contact 13-44. of relay ZRHR, and the winding of relay ZRASR to terminal C, and relay 2RASR accordingly picks up to close its front contact 45 and thus close its stick circuit which holds that relay energized when relay ZRTESR releases due to the interruption of its stick circuit at back contact 45 of relay 2RASR. With relay 2RASR picked up, the operator may now alter the previously established route.

It should be noted that the short time release is provided when time contact 25 of relay 2RTER. closes, thus differing from the long time release which utilizes both the heating and cooling time of relay ZRTER, that is, it requires that the heating time of the relay be utilized to close contact 25 and then that the cooling time of the relay be employed to close checking contact 26 prior to effecting the energizaticn of approach locking relay ZRASR. This long time release is of course self-checking in that the release cannot be established until after the time element relay is restored to its normal position as indicated by checking contact 25, hence there is avoided the possibility that a failure of time contact 25to return to its normal position might enable a subsequent operation of the time element relay to be completed in less than its predetermined time interval.

When the short time release is utilized, equivalent checking of the normal position of the time element relay is obtained by introducing into the control of all signals which are afforded a short time release, a contact controlled by relay ZRTER in its normal position. Thus, for example, the normal position of relay ZRTER is checked by interposing front contact 64 of relay ZRNTEPR, which relay is energized only if relay 2RTER occupies its normal position as indicated by the closure of checking contact 216, in the clearing circuits of signal unit 2RC or 2RD. It follows that if time contact 25 of relay ZRTER fails to return to its normal position but instead returns to a position such that another energization of the relay will close contact 25 in a time shorter than its predetermined time interval, contact 26 of the relay of course will not close, relay 2RNTEPR will remain released, and contact 64 of relay ZRNTEPR will remain open to prevent the clearing of signal unit 2RC or 2RD.

In the event that signal unit 2R0 is cleared as a call-on signal with a preceding train in section IT or O2T, and the following train accepts Relay 2RTESR, however, becomes energized at.

the end of the heating period of relay ZR'I'ER, due to the fact that under the assumed conditions the previously traced energizing circuit of,

relay 2RTER is completed at back contact 45-of relay ZRASR, and after relay QRTESR picks up, its front contact 15 closes to complete an obvious circuit for relay ZRASR, which circuit includes contact 75 of relay ZRTESR and reverse polar contact I344 of relay ZRHR. The energization of relay ZRASR of course releases the approach locking.

If, however, signal unit 2R0 is cleared as a 1 slow speed signal for a diverging move from section IT into diverging track 5, then switch 3 and repeater relay 3WPR are reversed and relay ZRHR. is energized in its reverse position so that when the train accepts signal 2R0 and enters section IT, the approach locking. may be released by restoring lever V to its normalposition wherein lever contact 31 is closed to complete a circuit for relay 2RASRextending from terminal B through contacts I8--I8b and. I9|9b of signal unit 2RD, 2R0 and 2RA, respectively, lever contact 31, back contact BI of relay ITR, front contact 14 of relay ZRHR and reverse polar contact I3--44 of relay 2RHR and the winding of relay ZRASR to terminal C.

From. the foregoing, it is readily apparent that signals and/or switches are controlled in accordance with our invention by means of a. very simple arrangement of circuits which involve a polarized relay 2RHR. The use of this relay .enables the main line signals to be slotted,

j the. signal control circuits, protection substantially equivalent to a double wire, double break system is afforded against improper routing caused by crosses, grounds, etc. Also, the circuits involving the polarized relay ZRHR are arranged to prevent a track circuit release of the approach locking when thev slow speed signal unit ZRC is employed as a. call-on signal, but which permits such track circuit release when the slow speed signal is employed to signal a diverging route. In addition, the use of relay 2RHR. permits progressive signaling in that if slow speed signal unit 2R0 has been cleared as a call-on signal and traffic conditions in advance change to permit the display of the high speed signal, signal unit. 2R0 automatically goes to stop and high speed signal unit 2-RA automatically clears if the following train has not accepted the callon signal. This progressive signaling feature, moreover, is effected while enforcing stick signaling principles on the call-on signal, in that afterthe call-on signal has been released due to the clearing of the high speed signal in response to traffic conditions on the main track, the call-on signal cannot be displayed auto matically when the following train accepts the high speed signal, but rather to restore the callon signal it is necessary for the operator again to actuate the call-on push button. Furthermore, the polarized relay ZRHR is incorporated into circuits which provide both long and short time releases for the approach locking, and wherein the return of a timing device to its normal position is checked for each long and short time release operation. In addition, the polarized relay permits the approach looking to be released in the regular manner for a high speed main track move even though the operator might neglect to restore the signal lever to its normal position.

Although we have herein shown and described only one form of railway traflic controlling apparatus embodying our invention, it is to be understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

1. In combination, a stretch of railway track including a track switch for establishing a high speed or a diverging route, a signal indicating proceed, slow speed or stop for governing the movement of trafiic over said routes, a polarized relay, means for energizing said relay in one direction over a circuit controlled by tramc on said stretch and by said switch and effective whentrafi'ic and switch conditions are suitable for the high speed route, other means for energizing said relay in the opposite direction when said switch is set for the diverging route, manually controllable means also eifective when said switch is set for the high speed route but trafiic conditions on said stretch are unfavorable for such route for energizing said polarized relay in said opposite direction, and means for controlling the signal to its proceed or its slow speed indication according as said relay is energized in its said one direction or is in its opposite position.

2. In combination, a stretch of railway track including a track switch for establishing a high speed or a diverging route, a signal indicating proceed, slow speed or stop for governing the movement of trafiic over said routes, a polarized relay, means for energizing said relay in one direction over a circuit controlled by traffic on said stretch and by said switch and effective when conditions are safe for said high speed route to be established, other means for energizing said relay in the opposite direction when said switch is set for the diverging route, manually controllable means effective when said switch is set for the high speed route but trafiic conditions on said stretch are unfavorable for such route for energizing said polarized relay in said opposite direction, circuit means for conditioning said signal to display its proceed or its slow speed indication according as said relay is energized in its said one direction or is in its opposite direction, and manually controllable means for rendering said circuit means active.

3. In combination, a stretch of railway track including a track switch, a signal for governing traffic over said stretch and switch, said signal normally indicating stop but operable to display proceed and slow speed indications, a polarized relay, means for energizing said relay in one direction over a circuit controlled by trafiic conditions on said stretch and by said switch and effective only when trafiic and switch conditions are favorable for the display of the proceedindication of said signal, other means effective when the condition of said switch is favorable for said proceed indication but traffic conditions in said stretch are unfavorable for such indicationfor conditioning said relay to be energized in its other direction for operating the relay to its reverse position, manually controllable means for rendering said other means active, and manually controllable means for operating said signal to its proceed or its slow speed indication ac cording as said relay is energized in said one direction or is in its reverse position.

4. In combination, a stretch of railway track including a track switch, a signal for governing traffic over said stretch and switch, said signal normally indicating stop but operable to display proceed and slow speed indications, manually operable means eifective in one position for controlling said signal to its stop indication and in another position for conditioning said signal to conditions on said stretch and by said switch and effective only when traffic and switch conditions are favorable for the display of the proceed indication of said signal, other means effective when the condition of said switch is unfavorable for the display of said proceed indication for conditioning said relay to be energized in its other direction for operating the relay to its reverse position, other manually controllable means for energizing said relay in its other direction when trafiic conditions are unfavorable for the display of said proceed indication, and means for controlling said signal to its proceed or its slow speed indication according as said relay is energized in said one direction or is in its reverse position.

5. In combination, a stretch of railway track including a track switch, a main signal indicating proceed, slow speed or stop for governing the movement of traffic over the stretch, another signal governing the movement of traffic into said stretch over said switch, a first relay having two positions one corresponding to traiiic movements over said stretch and the other corresponding to traffic movements into said stretch over said switch, a polarized relay, circuit means for normaly energizing said polarized relay in one direction controlled by said first relay and by traffic conditions in said stretch, other circuit means manually controllable when said stretch is occupied for energizing said polarized relay in the other direction, means governed by said first relay for operating said polarized relay to its other direction when said switch is set for traffic movements into said stretch, and circuit means controlled by said first relay and by said polarized relay for causing said main signal to indicate proceed or slow speed according as said polarized relay is energized in one direction or the other respectively and for causing said other signal to display proceed when both said first relay and said polarized relay occupy their respective other positions.

6 In combination, a stretch of railway trackincluding a track switch, a signal indicating proceed, slow speed and stop for governing the movement of trafiic over the stretch, a polarized relay, means for energizing said relay in one direction over a circuit controlled by trafiic on said stretch and by said track switch and effective when traffic and switch conditions are safe for said signal to indicate proceed, means for energizing said relay in its other direction over a circuit controlled by traffic on said stretch and by said track switch and eifective when traffic and switch conditions are unsafe for the signal to indicate proceed, means controlled by said relay for conditioning said signal to indicate proceed or slow speed according as said relay is in its said one or said other position, locking means rendered effective upon the approach of a train to the switch for preventing operation thereof, and means including a polar contact of said relay for at times rendering said locking means ineffective.

7. In combination, a stretch of railway track including a track switch, a detector track circuit for said switch, a polarized relay, means for energizing said relay in one direction over a circuit controlled by trafiic on said stretch and the position of said switch and efiective when conditions are favorable for a high speed move over said stretch, means for energizing said relay in its other direction over a circuit controlled by traflic on said stretch and the position of said switch and eifective when conditions are unfavorable for a high speed move over said stretch and said switch is conditioned for a high speed move, locking means rendered active upon the approach of a train to said switch for preventing operation thereof, and means rendered effective when said detector track circuit is occupied and controlled by said polarized relay for immediately rendering said locking means inactive when said polarized relay is in its said one direction but not when it is in its said other direction.

8. In combination, a stretch of railway track including a track switch, a polarized relay, means for energizing said relay in, one direction over a circuit controlled by trainc on said stretch and the position of said switch and effective when conditions are favorable for a high speed move over said stretch, means for energizing said relay in its other direction over a circuit controlled by trafiic on said stretch and the position of said switch and effective when traflic conditions are unfavorable for a high speed move over said stretch and said switch is conditioned for a high speed move, locking means rendered active upon the approach of a train to said switch for preventing operation thereof, and means controlled by trafiic on said stretch adjacent said switch and including a polar contact of said relay for immediately rendering said locking means inactive when said relay is in its said one position and for rendering said locking means inactive at the end of a predetermined time interval when said relay is in its said other position.

9. In combination, a stretch of railway track including a track switch, a polarized relay, means for energizing said relay in one direction over a circuit controlled by traffic on said stretch and the position of said switch and effective when conditions are favorable for a high speed move over said stretch, means for energizing said relay in its other direction over a circuit controlled by traflic on said stretch and the position of said switch and efiective when traffic conditions are unfavorable for a high speed move over said stretch and said switch is set for a high speed move, locking means rendered active upon the approach of a train to said switch for preventing operation thereof, and means responsive to a train on said stretch adjacent said switch for rendering said locking means immediately inactive when said relay is in its said one position but not when said relay is in its said other position.

10. In combination, a stretch of railway track including a track switch, a repeater relay controlled by said track switch, a polarized relay, circuit means controlled by traffic in said stretch and by said repeater relay for energizing said polarized relay in one direction when conditions are favorable for a high speed move through the stretch, other circuit means controlled by trafiic in said stretch and by said repeater relay for conditioning said polarized relay to be energized in its other direction when conditions require a low speed movement in said stretch, locking means rendered active upon the approach of a train to said switch for preventing operation thereof, means responsive to the entrance of the train on said stretch and including a polar contact of said polarized relay closed in its said one direction or a front contact and a polar contact of said polarized relay closed in its other direction for rendering said locking means inactive for train moves through said section but not over said switch.

11. In a traffic controlling system for railroads, the combination with a section of track provided with a track circuit and including a track switch, a high-speed signal and a low-speed signal governing traffic over said switch, of a polarized relay, means controlled by the position of said switch for energizing said relay with current of one relative polarity or the other according as said switch is set for a high-speed movement and said track circuit is unoccupied, or said switch is set for a low-speed movement, other means for energizing said relay with current of said other polarity when said switch is set for a highspeed movement and said track circuit is occupied, and means for clearing said high-speed signal or said low-speed signal according as said relay is energized by ciurent of said one or said other polarity.

12. In a trafiic controlling system for railroads, the combination with a section of track provided with a track circuit and including a track switch, a high-speed signal and a low-speed signal governing traflic over said switch, of a polarized relay, means controlled by the position of said switch for energizing said relay with current of one relative polarity or the other according as said switch is set for a high-speed movement and said track circuit is unoccupied, or said switch is set for a low-speed movement, other means for energizing said relay with current of said other polarity when said switch is set for a high-speed movement and said track circuit is occupied, and means also controlled by the position of said switch for clearing said highspeed signal or said low-speed signal according as said relay is energized by current of said one or said other polarity.

13. In a trafiic controlling system for railroads, the combination with a stretch of track including a track switch, a track circuit for a section in advance of said switch, and a high-speed signal and a low-speed signal governing trafiic over the switch, of a polarized relay, means for energizing said relay in one direction when said track circuit is unoccupied and said switch is set for a high-speed movement and for energizing said relay in the opposite direction when said switch is set for a low-speed movement, other means for energizing said-relay in said opposite direction when said track circuit is occupied and said switch is set for a high-speed movement,

and means for governing said high-speed signal or said low-speed signal according as said relay is energized in its said one or said opposite direction.

14. In a trafiic controlling system for railroads, the combination of a section of track provided with a track circuit and including a track switch, a high-speed signal and a low-speed signal governing trafiic over the switch, of a polarized relay, manually operable means for energizing said polarized relay in one direction when said track is unoccupied and said switch is positioned for a high-speed movement and for energizing said polarized relay in the opposite direction when said switch is positioned for a low-speed movement, other means for energizing said polarized relay in its said opposite direction when said track circuit is occupied and said switch is positioned for a high-speed movement, manually operable means for clearing said high speed signal or said low-speed signal according as said polarized relay is energized in its said one or said opposite direction, switch locking means rendered eiiective when either signal is cleared to prevent operation of said switch, a time measuring device for releasing said looking means under certain traflic conditions at the end of a measured time interval after a signal is manually put to stop, and means including a polar contact of said polarized relay for causing said time interval to be relatively long when said high-speed signal is put to stop and to be relatively short when said slow-speed signal is put to stop.

15. In combination with a detector section of railway track including a track switch, a section in approach of said section, a polarized relay of the type that retains its polar contacts in their last energized position, means for energizing said polarized relay with current of normal polarity when said detector section is unoccupied and said switch is set for a high-speed movement and for energizing said polarized relay with current of reverse polarity when said switch is set for a low-speed movement, manually operable means for momentarily energizing said polarized relay with current of said reverse polarity when said detector section is occupied and said switch is set for a high-speed movement, a locking relay which when deenergized prevents operation of said switch, a circuit for energizing said locking relay when said detector contact, or a reverse polar contact and a front contact of said polarized relay, and another circuit for energizing said locking relay including a reverse polar contact of said polarized relay and completed only at the end of a measured time interval after said detector section becomes occupied.

16. In combination with a detector section of railway track including a track switch, a section in approach of said section, a high-speed signal and a low-speed signal governing traiiic from said approach section over said switch, a polarized relay of the type that retains its polar contacts in their last energized position, means for energizing said polarized relay with current of normal polarity when said detector section is unoccupied and said switch is set for a highspeed movement and for energizing said polarized relay with current of reverse polarity when said switch is set for a low-speed movement, manually operable means for momentarily energizing said polarized relay with current of said reverse polarity when said detector section is occupied and said switch is set for a high-speed movement, manually operable means for clearing said high-speed signal or said low-speed signal according as their polar contacts of said polarized relay are in their normal or reverse positions respectively, a locking relay when when deenergized prevents operation of said switch, time measuring means for measuring two predetermined time intervals, a circuit effective if said approach section is occupied when a signal is manually put to stop and including a polar contact of said polarized relay, for energizing said locking relay at the end of the longer or the shorter of said two predetermined time intervals according as said polar contact is in its normal or in its reverse position, a circuit for energizing said locking relay when said detector section is occupied and including a normal polar contact, or a reverse polar contact and a front contact of said polarized relay, and another circuit for energizing said locking relay including a reverse polar contact of said polarized relay and completed only at the end of a measured time interval after said detector section becomes occupied.

EARL M. ALLEN. HENRY S. YOUNG.

' CERTIFICATE OF CORRECTION.

Patent No. 2,287,078. 1 June 25, 19142.

EARL M. ALLEN, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 9, sec- 0nd column, line 28, claim 16, for "their" read --the-; line 50, same claim, for "when when" read --which when--; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the casein the Patent Office.

Signed and sealed this hth day of August, A. D. 1914.2.

. Henry Van Arsdale, (Seal) I Acting Commissioner of Patents. 

